Certain braking devices having two brake pads, which cooperate with a brake rail or in a similar manner with a brake plate or brake disk, are conventional. For numerous applications, it is necessary to maintain a precise position of the movable part of an electric motor when stopping; that is, not only in the longitudinal direction of the brake rail, but also in the lateral directions, i.e., along the three main axes.
Most conventional braking devices of the type having brake pads have a main problem of changing the position of the movable part when operating the braking device. The device for distancing the two brake pads may produce deformations, in particular on the material that connects these two brake pads, these deformations consequently acting on the support of the assembly, which is formed by the two brake pads and the distancing device, on which support this assembly is rigidly fastened. Consequently, the change of the mechanical stresses in the braking device in its operation has the result of allowing the movable part of the motor, which is rigidly connected to the support, to move, in particular when activating the brake, in order to keep the movable part in a given position. In the case in which the two brake pads are rigidly connected by a connecting element that may experience a certain deflection, but which has the required stiffness when a braking force is exerted against the lateral walls of the brake rail, the change of the clearance of the two brake pads produces a deformation of this connecting element along the Z-axis (located in the center plane with respect to the two brake pads and perpendicularly with respect to the longitudinal direction of the brake rail). This deformation of the connecting element produces a change of position along the Z-axis of the support on which the connecting element is generally rigidly fastened.
Another problem encountered in braking devices of this kind results from the fact that the brake rail or the guide system of the movable part (which may be formed by the brake rail) is not always entirely straight. In such a case, it is possible that the brake disks, which are mounted on the brake pads, cause friction on the rail. The rigid construction of the conventional braking devices produces a significant braking effect at such frictions, which is unfavorable for the dynamic behavior of the electric motor.